If we consider the correct properties of an oven, we can say that “the oven not exceeding a maximum temperature threshold” is a safety property. The property of “the oven eventually reaching the temperature we specified via the button” is a liveness property.

Similar to this example, it’s usually more important in distributed systems to ensure the system satisfies the safety property than the liveness one.

The safety property weighs more than liveness in distributed systems.

Throughout this course, it will become clear that there is an inherent tension between safety and liveness properties. Actually, as we will see later in this course, there are some problems that make it physically impossible to satisfy both kinds of properties. So, we need to compromise some liveness properties to maintain safety.